Apparatus and method for managing emergency calls

ABSTRACT

A system that incorporates teachings of the present disclosure may include, for example, a network element operably couplable to an Internet Protocol Multimedia Subsystem network where the network element has a controller to receive an SIP request associated with a call, determine whether the SIP request comprises an identifier associated with an Emergency Call Session Control Function (E-CSCF) where the identifier was added to the SIP request by the E-CSCF, and provide the call to an emergency network when the identifier is associated with the E-CSCF. Other embodiments are disclosed.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to communication systems andmore specifically to an apparatus and method for managing emergencycalls.

BACKGROUND

Many emergency response services utilize Time DivisionMultiplexing-based systems as an interface for their public safetyanswering points. Such E911 networks often have a limited allocation ofE911 trunks. IP Multimedia Subsystem networks can utilize Emergency CallSession Control Functions to connect with the E911 trunks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 depict illustrative embodiments of communication systems thatprovide media services;

FIGS. 4a and 4b depict illustrative embodiments of methods operating inportions of the communication systems of FIGS. 1-3; and

FIG. 5 is a diagrammatic representation of a machine in the form of acomputer system within which a set of instructions, when executed, maycause the machine to perform any one or more of the methodologiesdiscussed herein.

DETAILED DESCRIPTION

One embodiment of the present disclosure can entail computer-readablestorage medium of a Media Gateway Control Function (MGCF) operablycoupled to an Internet Protocol Multimedia Subsystem (IMS) network,where the storage medium includes computer instructions to receive atthe MGCF an SIP INVITE associated with a call, determine whether the SIPINVITE has a header associated with emergency calls, determine whetherthe header comprises an identifier associated with an Emergency CallSession Control Function (E-CSCF) where the identifier was added to theheader by the E-CSCF, and provide the call to an emergency network whenthe identifier is associated with the E-CSCF.

Another embodiment of the present disclosure can entail a networkelement operably couplable to an Internet Protocol Multimedia Subsystemnetwork, the network element having a controller to receive an SIPrequest associated with a call, determine whether the SIP requestcomprises an identifier associated with an Emergency Call SessionControl Function (E-CSCF) where the identifier was added to the SIPrequest by the E-CSCF, and provide the call to an emergency network whenthe identifier is associated with the E-CSCF.

Yet another embodiment of the present disclosure can entail a networkelement operably couplable to an Internet Protocol Multimedia Subsystem(IMS) network, the network element having a controller adapted toreceive from a Proxy Call Session Control Function an SIP requestassociated with a call, add an identifier to the SIP request where theidentifier is associated with the network element and identifies thenetwork element as an Emergency Call Session Control Function, providethe SIP request with the identifier to a Breakout Gateway ControlFunction, where the call is provided to an emergency network based on arecognition of the identifier.

Yet another embodiment of the present disclosure can entail acommunication device for an Internet Protocol Multimedia Subsystem (IMS)network, the device having a controller adapted to register with a ProxyCall Session Control Function (P-CSCF) using an SIP request tocommunicate with an emergency network where an identifier is added tothe SIP request by an Emergency Call Session Control Function (E-CSCF)where the identifier is associated with the E-CSCF and where the call isprovided to the emergency network based on a recognition of theidentifier by a Media Gateway Control Function (MGCF).

Yet another embodiment of the present disclosure can entail receiving ata Media Gateway Control Function an SIP INVITE associated with a call,determining whether the SIP INVITE comprises an identifier associatedwith an Emergency Call Session Control Function (E-CSCF) wherein theidentifier was added to the header by the E-CSCF and where the SIPINVITE was provided by the E-CSCF, and providing the call to anemergency network when the identifier is associated with the E-CSCF.

FIG. 1 depicts an illustrative embodiment of a communication system 100.employing an IP Multimedia Subsystem (IMS) network architecture tofacilitate the combined services of circuit-switched and packet-switchedsystems. Communication system 100 can be overlaid or operably coupledwith other communication systems including PSTN systems, iTV systems andthe like, for communication of voice, video, and/or other data.

Communication system 100 can comprise a Home Subscriber Server (HSS)140, a tElephone NUmber Mapping (ENUM) server 130, and other commonnetwork elements of an IMS network 150. The IMS network 150 canestablish communications between IMS compliant communication devices(CD) (such as IMS User Endpoint Devices as described in the IMSstandard) 101, 102, Public Switched Telephone Network (PSTN) CDs (suchas Customer Premises Equipment) 103, 105, and combinations thereof byway of a Media Gateway Control Function (MGCF) 120 coupled to a PSTNnetwork 160.

IMS CDs 101, 102 can register with the IMS network 150 by contacting aProxy Call Session Control Function (P-CSCF) which communicates with acorresponding Serving CSCF (S-CSCF) to register the CDs with the HSS140. To initiate a communication session between CDs, an originating IMSCD 101 can send a Session Initiation Protocol (SIP INVITE) message orrequest to an originating P-CSCF 104 which communicates with acorresponding originating S-CSCF 106. The originating S-CSCF 106 cansubmit queries to the ENUM system 130 to translate an E.164 telephonenumber in the SIP INVITE to a SIP Uniform Resource Identifier (URI) ifthe terminating communication device is IMS compliant.

The SIP URI can be used by an Interrogating CSCF (I-CSCF) 107 to submita query to the HSS 140 to identify a terminating S-CSCF 114 associatedwith a terminating IMS CD such as reference 102. Once identified, theI-CSCF 107 can submit the SIP INVITE to the terminating S-CSCF 114. Theterminating S-CSCF 114 can then identify a terminating P-CSCF 116associated with the terminating CD 102. The P-CSCF 116 then signals theCD 102 to establish communications.

If the terminating communication device is instead a PSTN CD such asreferences 103 or 105, the ENUM system 130 can respond with anunsuccessful address resolution which can cause the originating S-CSCF106 to forward the call to the MGCF 120 via a Breakout Gateway ControlFunction (BGCF) 119. The MGCF 120 can then initiate the call to theterminating PSTN CD by common means over the PSTN network 160.

The aforementioned communication process is symmetrical. Accordingly,the terms “originating” and “terminating” in FIG. 1 are interchangeable.It is further noted that communication system 100 can be adapted tosupport video conferencing by way of common protocols such as H.323. Inaddition, communication system 100 can be adapted to provide the IMS CDs201, 203 with the multimedia and Internet services of an IPTV or othernetwork having multimedia capability.

In one embodiment, some of the network elements of the system 100 can becoupled to one or more computing devices, a portion of which can operateas a web server for providing portal services over an Internet ServiceProvider (ISP) network to wireline media devices or wirelesscommunication devices by way of a wireless access base station operatingaccording to common wireless access protocols such as Wireless Fidelity(WiFi), or cellular communication technologies (such as GSM, CDMA, UMTS,WiMAX, Software Defined Radio or SDR, and so on).

In one embodiment, system 100 can utilize Media Gateways (MGWs) toprovide connectivity for legacy Time Division Multiplexing (TDM)-basedservices, such as traditional PSTN, GSM, and E911 PSAPs. The MGWs canprovide inter-working between RTP/UDP/IP voice packet streams andcircuit-based TDM voice trunks. For instance, a set of TDM trunks can bespecialized to connect to an E911 tandem switch (such as an E911selective router) that provides connectivity and E911 call routing toappropriate PSAP offices. Coupling with a set of MGWs, MGCF 120,including its signaling gateway functions, can control the MGs forbearer path management and can provide call signaling interworkingbetween the SIP-based VoIP networks and the legacy ISUP-based TDMnetworks.

As an example, system 100 can utilize Emergency Call Session ControlFunction (E-CSCF) 151 for processing E911 calls to an E911 trunk (suchas in E911 network 175) by way of MGCF 120. System 100 can provide forthe E-CSCF 151 handling the E911 calls while normal outgoing calls arehandled by S-CSCF 106 through use of identification informationassociated with the E-CSCF that will be recognized by an MGCF that isresponsible for controlling E911 trunks. In one embodiment, the IMS UEscan make 911 call via E-CSCF even if the UEs have not successfullyregistered with the IMS system 100.

FIG. 2 depicts an illustrative embodiment of a communication system 200.employing an IP Multimedia Subsystem (IMS) network architecture tofacilitate the combined services of circuit-switched and packet-switchedsystems, and to support E911 calls. Communication system 200 can beoverlaid or operably coupled with communication system 100 as anotherrepresentative embodiment of said communication system.

System 200 depicts various components of an IMS-based system thatsupports E911 calls, including a user end point device 201, a P-CSCF 204and an S-CSCF 206. Other components not shown in FIG. 2 can also be usedwith system 200, including ENUM 130 and HSS 140 of FIG. 1. System 200can include one or more E-CSCFs 251 (only one is shown) for processingof E911 calls. The E-CSCF 251 can be in communication with a Location &Routing Function (LRF) 225. For example, the E-CSCF 251 can contact theLRF 225 to obtain location information and routing information, whichcan then be used to direct the call to the appropriate PSAP that servesthe location where the 911 call is being made. Various invite, ISUP IAMand/or register messages can be utilized to process E911 calls andnormal or non-E911 calls by system 200.

In one embodiment, E-CSCF 251 can be provisioned with, or otherwise hasaccess to, an E-CSCF instance identifier 255. The E-CSCF 251 can add itsE-CSCF identifier 255 to a header of an SIP INVITE that is forwarded tothe BGCF and MGCF so that the E911 call can be confirmed as beingreceived from the appropriate E-CSCF. An E-CSCF identifier 255 can beunique to each of the E-CSCFs of system 200 or can be unique for morethan one of the E-CSCFs, including all of the E-CSCFs. For instance, theheader can be a service provider's proprietary header, such asX-ATT-ECSCF and can be included in the SIP INVITE messages. The headercan carry the E-CSCF ID in an SIP INVITE. The header can be supported byboth E-CSCF and MGCF in their implementation. Each of the E-CSCFs can beprovisioned with an identifier, such as ID₁ of FIG. 3. The identifiercan be unique in the entire network. Each MGCF that is capable ofhandling E911 calls can be provisioned with the identifiers for each ofthe E-CSCFs. For instance, each time a new E-CSCF is deployed in the NGNnetwork, administrative staff can configure the E-CSCF ID in E-CSCF andin the MGCF; and every time when an E-CSCF is removed from the NGNnetwork, the administrative staff can remove the E-CSCF ID from theMGCF.

FIG. 3 depicts an illustrative embodiment of a communication system 300.employing an IP Multimedia Subsystem (IMS) network architecture tofacilitate the combined services of circuit-switched and packet-switchedsystems, and to support E911 calls. Communication system 300 can beoverlaid or operably coupled with communication system 100 and 200 asanother representative embodiment of said communication systems. FIG. 3depicts signal flow associated with E911 calls and signal flowassociated with normal or non-E911 calls. As described below, system 300provides for confirmation that an E911 call is being received from anappropriate E-CSCF so that the E911 trunks do not become overloaded,such as due to false or otherwise bogus E911 calls.

System 300 depicts various components of an IMS-based system thatsupports E911 calls, including a user end point device 301, a P-CSCF304, an S-CSCF 306, a BGCF 319, an MGCF 320 (including MGW), an LRF 325,application servers 335 and an E-CSCF 351. While this exemplaryembodiment depicts only one of each of these components, the presentdisclosure contemplates other numbers and/or configurations of thesecomponents. Other components not shown in FIG. 3 can also be used withsystem 300, including ENUM 130 and HSS 140 of FIG. 1.

E-CSCF 351 can process E911 calls through use of Session InitiationProtocol. The E-CSCF 351 can be provisioned with, or otherwise haveaccess to, one or more E-CSCF identifiers 355, which can be added by theE-CSCF to a header of an SIP INVITE that is then forwarded to the BGCF319 and MGCF 320 so that the E911 call can be confirmed as beingreceived from the appropriate E-CSCF. The MGCF 320 can be provisionedwith, or otherwise have access to, a set of identifiers 321 thatincludes the E-CSCF identifiers 355 to perform the confirmation. Onceconfirmed, the MGCF 320 can process the E911 call to an E911 trunk ofE911 network 375. An E911 identifier 355 can be unique to each of theE-CSCFs of system 300 or can be unique for more than one of the E-CSCFs,including all of the E-CSCFs. Normal or non-E911 calls can be processedvia SIP messaging through the S-CSCF 306, the BGCF 319, and the MGCF 320to the PSTN network 360.

FIG. 4a depicts an illustrative method 400 operating in portions ofcommunication systems 100-300. Method 400 can be a process flow for theE-CSCF. Beginning with step 406, a ready state is provided where theprocess waits for invite requests. In step 408, the process can receivea call or invite request and in step 410 determine if a 911 call hasbeen received. If the call is not a 911 call then in step 412 the callcan be rejected and the process can return to its ready state in step406. If on the other hand the call is a 911 call then in step 416, theE-CSCF can insert the E-CSCF instance's E-CSCF-ID into the SIP INVITEmessage in the header. The E-CSCF can then send the SIP INVITE messagetowards the MGCF by way of the BGCF in step 418.

FIG. 4b depicts an illustrative method 401 operating in portions ofcommunication systems 100-300. Method 401 can be a process flow for theMGCF. Beginning with step 450, a ready state is provided where theprocess waits for invite requests. In step 452, the process can receivean INVITE and in step 454 determine if the call is a 911 call. If thecall is not a 911 call then in step 456 the MGCF processes the call asnormal. If on the other hand the call is a 911 call then in step 458,the process can determine if an E-CSCF-ID is present in the INVITE andwhether it matches a stored E-CSCF-ID. If the appropriate E-CSCF-ID isnot present then in step 460 the call can be rejected. If on the otherhand the appropriate E-CSCF-ID is present then in step 462 the call canbe processed as a 911 call.

The exemplary embodiments allow the MGCF to confirm or otherwisedetermine that the 911 call was received from an E-CSCF, rather thanfrom other call servers (such as from a S-CSCF where the call wasincorrectly identified as an E911 call due to a corrupted profile or thelike or due to a malicious attack on the system). In one embodiment,where the MGCF rejects the SIP request based on the lack of the headeror the lack of a known identifier associated with an E-CSCF, then theMGCF or another device can monitor for such rejections. An alarm orother notice can be provided, such as to a system or networkadministrator, where a number of rejections satisfies an alarmthreshold. For instance, an alarm can be sent to the administrator whena predetermined number of false E911 calls (such as rejected requests instep 416) are generated by the same user end point device. Other factorsfor generating the alarm can also be utilized, including a predeterminednumber of false E911 calls from a geographic region or over a specifiedtime from one or more user end point devices.

Upon reviewing the aforementioned embodiments, it would be evident to anartisan with ordinary skill in the art that said embodiments can bemodified, reduced, or enhanced without departing from the scope andspirit of the claims described below. For example, the provisioning ofthe E911 identifiers to each of the E-CSCFs and the MGCF that handlesE911 calls can be done dynamically. For instance, topology informationcan be monitored so that the MGCF is automatically provisioned with E911identifiers based on a current topology of the network. Where an E-CSCFis added or removed (or not functioning), the MGCF can be made aware ofthis information and can be provided with the corresponding E911identifier, such as through a monitoring server operably coupled to theE-CSCFs and the MGCF. In one embodiment, a source of false or bogus E911calls can be determined, such as by the MGCF, and communicated to anetwork administrator.

In another embodiment, the E911 identifiers can be dynamic. For example,an E-CSCF can be associated with a group of E911 identifiers. The MGCFcan be provisioned with the entire group of E-911 identifiers. Theparticular E911 identifier within the group that is utilized for a givenE911 call can be changed based on a particular factor (including anencryption key, sequentially, etc.), which is known to the MGCF, toreduce or prevent malicious attacks.

Other suitable modifications can be applied to the present disclosurewithout departing from the scope of the claims below. Accordingly, thereader is directed to the claims section for a fuller understanding ofthe breadth and scope of the present disclosure.

FIG. 5 depicts an exemplary diagrammatic representation of a machine inthe form of a computer system 500 within which a set of instructions,when executed, may cause the machine to perform any one or more of themethodologies discussed above. In some embodiments, the machine operatesas a standalone device. In some embodiments, the machine may beconnected (e.g., using a network) to other machines. In a networkeddeployment, the machine may operate in the capacity of a server or aclient user machine in server-client user network environment, or as apeer machine in a peer-to-peer (or distributed) network environment.

The machine may comprise a server computer, a client user computer, apersonal computer (PC), a tablet PC, a laptop computer, a desktopcomputer, a control system, a network router, switch or bridge, or anymachine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. It will beunderstood that a device of the present disclosure includes broadly anyelectronic device that provides voice, video or data communication.Further, while a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein.

The computer system 500 may include a processor 502 (e.g., a centralprocessing unit (CPU), a graphics processing unit (GPU, or both), a mainmemory 504 and a static memory 506, which communicate with each othervia a bus 508. The computer system 500 may further include a videodisplay unit 510 (e.g., a liquid crystal display (LCD), a flat panel, asolid state display, or a cathode ray tube (CRT)). The computer system500 may include an input device 512 (e.g., a keyboard), a cursor controldevice 514 (e.g., a mouse), a disk drive unit 516, a signal generationdevice 518 (e.g., a speaker or remote control) and a network interfacedevice 520.

The disk drive unit 516 may include a machine-readable medium 522 onwhich is stored one or more sets of instructions (e.g., software 524)embodying any one or more of the methodologies or functions describedherein, including those methods illustrated above. The instructions 524may also reside, completely or at least partially, within the mainmemory 504, the static memory 506, and/or within the processor 502during execution thereof by the computer system 500. The main memory 504and the processor 502 also may constitute machine-readable media.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Applications that may include the apparatusand systems of various embodiments broadly include a variety ofelectronic and computer systems. Some embodiments implement functions intwo or more specific interconnected hardware modules or devices withrelated control and data signals communicated between and through themodules, or as portions of an application-specific integrated circuit.Thus, the example system is applicable to software, firmware, andhardware implementations.

In accordance with various embodiments of the present disclosure, themethods described herein are intended for operation as software programsrunning on a computer processor. Furthermore, software implementationscan include, but not limited to, distributed processing orcomponent/object distributed processing, parallel processing, or virtualmachine processing can also be constructed to implement the methodsdescribed herein.

The present disclosure contemplates a machine readable medium containinginstructions 524, or that which receives and executes instructions 524from a propagated signal so that a device connected to a networkenvironment 526 can send or receive voice, video or data, and tocommunicate over the network 526 using the instructions 524. Theinstructions 524 may further be transmitted or received over a network526 via the network interface device 520.

While the machine-readable medium 522 is shown in an example embodimentto be a single medium, the term “machine-readable medium” should betaken to include a single medium or multiple media (e.g., a centralizedor distributed database, and/or associated caches and servers) thatstore the one or more sets of instructions. The term “machine-readablemedium” shall also be taken to include any medium that is capable ofstoring, encoding or carrying a set of instructions for execution by themachine and that cause the machine to perform any one or more of themethodologies of the present disclosure.

The term “machine-readable medium” shall accordingly be taken toinclude, but not be limited to: solid-state memories such as a memorycard or other package that houses one or more read-only (non-volatile)memories, random access memories, or other re-writable (volatile)memories; magneto-optical or optical medium such as a disk or tape;and/or a digital file attachment to e-mail or other self-containedinformation archive or set of archives is considered a distributionmedium equivalent to a tangible storage medium. Accordingly, thedisclosure is considered to include any one or more of amachine-readable medium or a distribution medium, as listed herein andincluding art-recognized equivalents and successor media, in which thesoftware implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the disclosure is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are periodicallysuperseded by faster or more efficient equivalents having essentiallythe same functions. Accordingly, replacement standards and protocolshaving the same functions are considered equivalents.

The illustrations of embodiments described herein are intended toprovide a general understanding of the structure of various embodiments,and they are not intended to serve as a complete description of all theelements and features of apparatus and systems that might make use ofthe structures described herein. Many other embodiments will be apparentto those of skill in the art upon reviewing the above description. Otherembodiments may be utilized and derived therefrom, such that structuraland logical substitutions and changes may be made without departing fromthe scope of this disclosure. Figures are also merely representationaland may not be drawn to scale. Certain proportions thereof may beexaggerated, while others may be minimized. Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense.

Such embodiments of the inventive subject matter may be referred toherein, individually and/or collectively, by the term “invention” merelyfor convenience and without intending to voluntarily limit the scope ofthis application to any single invention or inventive concept if morethan one is in fact disclosed. Thus, although specific embodiments havebeen illustrated and described herein, it should be appreciated that anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separately claimed subject matter.

What is claimed is:
 1. An article of manufacture comprising computerreadable instructions that, when executed by a processor, cause amachine to perform operations including: receiving, at a Media GatewayControl Function, a session initiation protocol INVITE associated with acall; determining whether the session initiation protocol INVITE has aheader associated with emergency calls; determining whether the headerincludes an Emergency Call Session Control Function identifierprovisioned in the Emergency Call Session Control Function and added tothe header by the Emergency Call Session Control Function, the EmergencyCall Session Control Function identifier being unique to the EmergencyCall Session Control Function; and providing the call to an emergencynetwork when the Emergency Call Session Control Function identifier isin the header.
 2. The article of manufacture of claim 1, wherein theinstructions further cause the machine to determine whether the call isan E911 call.
 3. The article of manufacture of claim 1, wherein theinstructions further cause the machine to reject the session initiationprotocol INVITE when the session initiation protocol INVITE does nothave the header associated with the emergency calls.
 4. The article ofmanufacture of claim 3, wherein the instructions further cause themachine to reject the session initiation protocol INVITE when the headerassociated with the emergency calls does not include the Emergency CallSession Control Function identifier.
 5. The article of manufacture ofclaim 1, wherein the instructions further cause the machine to: rejectthe session initiation protocol INVITE when the header associated withthe emergency calls does not include the Emergency Call Session ControlFunction identifier; monitor for rejections; and provide a notificationwhen the monitored rejections satisfy an alarm threshold.
 6. The articleof manufacture of claim 1, wherein the instructions further cause themachine to store one or more Emergency Call Session Control Functionidentifiers associated with a plurality of Emergency Call SessionControl Functions of an Internet Protocol Multimedia Subsystem network.7. The article of manufacture of claim 1, wherein the session initiationprotocol INVITE is received from a Breakout Gateway Control Function. 8.The article of manufacture of claim 1, wherein the instructions furthercause the machine to: reject the session initiation protocol INVITE whenthe session initiation protocol INVITE does not have the headerassociated with the emergency calls; monitor for rejections; and providea notification when the monitored rejections satisfy an alarm threshold.9. A network element comprising: a memory including machine readableinstructions; and a processor to execute the instructions to: determinewhether a session initiation protocol request includes an Emergency CallSession Control Function identifier added to a header by an EmergencyCall Session Control Function, the Emergency Call Session ControlFunction identifier being unique to the Emergency Call Session ControlFunction; and provide a call to an emergency network when the EmergencyCall Session Control Function identifier is in the header.
 10. Thenetwork element of claim 9, wherein the processor is to: store aplurality of Emergency Call Session Control Function identifiers; anddetermine whether the session initiation protocol request includes theEmergency Call Session Control Function identifier by comparing theEmergency Call Session Control Function identifier with the plurality ofEmergency Call Session Control Function identifiers.
 11. The networkelement of claim 9, wherein the header is associated with emergencycalls, and the processor is to reject the session initiation protocolrequest when the session initiation protocol request does not have theheader associated with the emergency calls.
 12. The network element ofclaim 11, wherein the processor is to reject the session initiationprotocol request when the header associated with the emergency callsdoes not include the Emergency Call Session Control Function identifier.13. The network element of claim 12, wherein the processor is to:monitor for rejections; and provide a notification when the monitoredrejections satisfy an alarm threshold.
 14. An Emergency Call SessionControl Function network element comprising: a memory including machinereadable instructions; and a processor to execute the instructions to:access a session initiation protocol request associated with a call, thesession initiation protocol request received from a Proxy Call SessionControl Function; add an identifier to the session initiation protocolrequest, the identifier to uniquely identify the Emergency Call SessionControl Function network element; and provide the session initiationprotocol request with the identifier to a Breakout Gateway ControlFunction, the call to be provided to an emergency network based on arecognition of the identifier.
 15. The Emergency Call Session ControlFunction network element of claim 14, wherein the identifier is added toa header of the session initiation protocol request, the header beingassociated with emergency calls.
 16. The Emergency Call Session ControlFunction network element of claim 14, wherein the recognition of theidentifier is to be performed by a Media Gateway Control Function of anInternet Protocol Multimedia Subsystem network.
 17. The Emergency CallSession Control Function network element of claim 14, wherein theprocessor is to obtain location and routing information from a Locationand Routing Function of the Internet Protocol Multimedia Subsystemnetwork.
 18. The Emergency Call Session Control Function network elementof claim 14, wherein the identifier is from a plurality of identifiersassociated with the network element and accessible by the processor, andthe processor is to select one identifier from among the plurality ofidentifiers.
 19. A communication device: a memory including machinereadable instructions; and a processor to execute the instructions to:register with a Proxy Call Session Control Function using a sessioninitiation protocol request to communicate with an emergency network, anEmergency Call Session Control Function identifier provisioned in anEmergency Call Session Control Function added to the session initiationprotocol request by the Emergency Call Session Control Function, theEmergency Call Session Control Function identifier unique to theEmergency Call Session Control Function, and the call to be provided tothe emergency network based on a recognition of the Emergency CallSession Control Function identifier by a Media Gateway Control Function.20. The communication device of claim 19, wherein the Media GatewayControl Function is to store a plurality of Emergency Call SessionControl Function identifiers associated with a plurality of EmergencyCall Session Control Functions of the Internet Protocol MultimediaSubsystem network.
 21. A method, comprising: associating, by executingan instruction with a processor, an identifier with an Emergency CallSession Control Function, the identifier unique to the Emergency CallSession Control Function; provisioning, by executing an instruction withthe processor, a Media Gateway Control Function with the identifier; andproviding, by executing an instruction with the Emergency Call SessionControl Function, a call to an emergency network when the Emergency CallSession Control Function adds its provisioned identifier in a sessioninitiation protocol INVITE associated with the call.
 22. The method ofclaim 21, further including provisioning the Emergency Call SessionControl Function with the identifier and using the Emergency CallSession Control Function to add the identifier to a header of thesession initiation protocol INVITE.
 23. The method of claim 22, furtherincluding: rejecting the session initiation protocol INVITE when theheader associated with the emergency call does not include theidentifier; monitoring for rejections; and providing a notification whenthe monitored rejections satisfy an alarm threshold.
 24. The method ofclaim 21, further including: rejecting the session initiation protocolINVITE when the session initiation protocol INVITE does not include theidentifier; monitoring for rejections; and providing a notification whenthe monitored rejections satisfy an alarm threshold.
 25. The method ofclaim 21, further including determining whether the call is an E911call.